Drift Step Recovery Diodes Research Articles

Evaluation of DSRD-based pulsers for a Dielectric Wall Accelerator

Silicon (Si) drift step recovery diodes (DSRD) are opening switches that form the basis for nanosecond-scale high voltage (HV) pulsers. These pulsers are crucial to the operation of a dielectric wall accelerator (DWA), a compact particle accelerator design for proton beam radiation therapy. For the DWA to operate properly, the pulser must generate HV pulses with fast rise times and widths on the order of 1 ns at an operating frequency above 1 kHz. Several pulser designs are available that can optimally drive DSRDs. The purpose of this study is to investigate the capabilities of two DSRD-based pulsers in the context of the DWA and the required pulse parameters. The first pulser is based on a magnetic saturation transformer (MST) and a DRSD. The second pulser considered is a multi-module MOSFET-DSRD-based pulser. Additionally, Sentaurus TCAD simulations are used to study the influence of the Si DSRD doping profile on the output pulse shape. The MST-DSRD-based pulser is able to generate higher amplitude pulses than the MOSFET-DSRD-based pulser with a single module (9645 V and 1807 V, respectively). However, the multi-module MOSFET-DSRD-based pulser achieves the maximum pulse amplitude (10.9 kV) compared to MST-DSRD-based pulser (9645 V). The MOSFET-DSRD-based pulser also generates pulses with shorter pulse widths compared to the MST-DSRD-based pulser (minimum of 3 ns vs. minimum of 8.36 ns, respectively). With no compression stage, the MOSFET-DSRD-based pulser (with more than one module) generates pulses with consistently faster rise times (≤3.06 ns) compared to the MST-DSRD-based pulser (≤4.31 ns). With a compression stage, the rise times were comparable between the two pulsers (MOSFET-DSRD: 1.66 ns and MST-DSRD: 1.48 ns). Both pulsers are able to operate at 1 kHz and the MOSFET-DSRD-based pulser up to 10 kHz. Parasitic capacitance and coupling between modules of the MOSFET-DSRD-based pulser affect the pulse through their influence on the forward and reverse pumping duration. Simulations show that the p region of the DSRD should be larger than the n doped region. Simulations including a parasitic capacitance, modelling the electrical connections to the DSRD, reduce the pulse amplitude. Simulations of the pulsers incorporating SiC DSRDs show a reduction in the pulse amplitude and a widening of the pulse width in comparison to the Si DSRDs.

Collaborative Design of Pulsed-Power Generator Based on SiC Drift Step Recovery Diode

Collaborative Design of Pulsed-Power Generator Based on SiC Drift Step Recovery Diode

A solid-state pulse power sub-nanosecond SiC DSRD-based generator with high-voltage and high repetition frequency for pulse discharge water treatment

Water treatment is one of the most important issues for all walks of life around the world. The unique advantages of the solid-state power electronic pulses in water treatment make it attractive and promising in practical applications. The output voltage, rising time, repetition rate, and peak power of output pulses have a significant impact on the effectiveness of water treatment. Especially in pulse electric field treatment and pulse discharge treatment, the pulse with fast rising time achieves the advantage of generating plasma without corona, which can avoid water heating effect and greatly improve the efficiency of the pulse generator. High repetition rate can significantly reduce the peak power requirement of the pulse in water treatment application, making the equipment smaller and improving the power density. Therefore, the study developed a high-voltage high frequency sub-nanosecond pulse power generator (PPG) system for wastewater treatment. It adopts SiC DSRD (Drift Step Recovery Diode) solid-state switches and realize modular design, which can achieve high performance and can be flexible expanded according to the requirements of water treatment capacity. Finally, an expandable high-voltage PPG for water treatment is built. The output parameters of the PPG include output pulse voltage range from 1 to 5.28 kV, rise time <600 ps (20%–90%), repetition up to 1 MHz. The experiment results of PPG application for pulse discharge water treatment is presented. The results indicate that the proposed generator achieves high-efficiency degradation of 4-Chlorophenol (4-CP), which is one of the most common chlorophenol compounds in wastewater. From experiment, the homemade system can degrade 450 mL waste water containing 500 mg/L 4-CP in 35 min, with a degradation rate of 98%. Thereby, the requirement for electric field intensity decreased. Through the further quantitative analysis, the impact of frequency, voltage, and electrode spacing on the degradation effect of 4-CP is confirmed.

Investigation of Prepulse of SiC Drift Step Recovery Diode in Fast Interruption Process

Investigation of Prepulse of SiC Drift Step Recovery Diode in Fast Interruption Process

New concept of two-cascade energy compression systems based on drift step recovery diodes

A new concept of effective high-voltage nanosecond pulse generators based on two compression cascades of drift step recovery diodes (DSRDs) is presented. The main advantage of the proposed approach arises from the decoupling of the operation cycles of DSRD cascades while using a single primary switch. This greatly improves the overall efficiency of the system. The first DSRD cascade operates with low pulse current densities. Its operation cycles can be extended resulting in an increase of the compression factor and pulse energy, whereas the loss level is kept at a minimum. The second DSRD cascade operates with high current densities, but the duration of its cycles can be chosen much shorter which ensures good efficiency too. Furthermore, an extension of the working cycle of the first DSRD cascade makes the requirement for the primary switch milder so that even relatively slow low-voltage switches can be employed.

Impact of temperature on dynamic characteristics of 4H-silicon carbide drift step recovery diodes

Silicon carbide (SiC) has advantages in high-temperature applications due to its high thermal conductivity and intrinsic temperature. However, the temperature also affects its physical properties thus the electrical characteristics of SiC-based devices. In this paper, the impact of temperature on the dynamic characteristics of 4H-SiC drift step recovery diode (DSRD) is studied. Both the pulse experiments and the two-dimensional numerical simulations are conducted at variable input voltage (Vin). The results show that both the peak value (Vpeak) of the output pulse voltage and the rising rate (dV/dt) of the pulse front decrease with the increased temperature. As the temperature rises from 25 °C to 125 °C, the Vpeak decreases from 1224 V to 820 V at Vin = 120 V, with a decrease ratio of 33 %. The dV/dt decreases from 214 V/ns to 92 V/ns at Vin = 100 V, with a decrease ratio of 57 %. The main reason for this phenomenon is that the increase in temperature leads to a significant decrease in carrier mobility. This work is of certain reference significance for the application of 4H-SiC DSRD in high-temperature situations.

Characteristics comparison of SiC and Si drift step recovery diode

In order to evaluate the prospects of drift step recovery diode (DSRD) based on Silicon Carbide (SiC) in pulsed power field, the characteristics of DSRD based on SiC and Silicon (Si) are compared. The simulation model of the circuit based on Sentaurus TCAD is established and a trigger circuit using the saturated transformer is adopted. The simulation results show that under the same conditions, SiC DSRD has advantages in the aspect of rise time and it is less affected by pedestal effect, which is detrimental to the pulse quality and produces energy loss. The advantage of Si DSRD is that the amplitude of the output pulse voltage is high. By testing the voltage and the rise time of the output pulse, the influence of different factors including turns ratio and input voltage are discussed. For single chip of SiC DSRD with 5 kV blocking voltage, the turns ratio of transformer should be 1:5 to ensure that the parasitic inductance of transformer is low and the input voltage should be more than 500 V to guarantee that the magnetic core can be saturated. For Si DSRD stacked in series, the rise time and the width of output pulse is relatively stable and have little correlation with the changes of the input voltage, the forward pumping time and the circuit parameters. The experiment proves that SiC DSRD and Si DSRD have the advantages of the rise time and the output pulse voltage, respectively, which is consistent with the simulation results.

Influence of DSRD Operation Cycle on the Output Pulse Parameters

Drift step recovery diodes (DSRDs) are semiconductor opening switches designed for the forming of high-voltage nanosecond pulses. DSRD-based circuit includes inductive energy storage and works as a high-efficient compression stage of the tens to hundreds of nanoseconds input pulse down to nanosecond or subnanosecond range output pulse. Despite the well-investigated physical principles, a lot of published DSRD simulations, and practical DSRD-based pulsers, the fundamental research aimed at optimization of DSRD circuit has not been conducted yet. The present letter shows the result of extensive experiments elucidating the maximum voltage rise rate, pulse compression ratio, energy losses, and prepulse amplitude in DSRD circuits. The explicit definitions of DSRD pulse parameters, which are vital for the optimization process, are suggested for the first time. It is demonstrated that optimizations of different parameters contradict each other, and there is no universal optimal solution. The compromise should be found for each application using the recommendations presented in the letter.

A Generator of Powerful Nanosecond Pulses Based on a Module of Drift Step Recovery Diodes and a Module of Shock-Ionized Dynistors

A Generator of Powerful Nanosecond Pulses Based on a Module of Drift Step Recovery Diodes and a Module of Shock-Ionized Dynistors

Dynamic Electrical Characteristics of 4H-SiC Drift Step Recovery Diodes of High Voltage

In order to evaluate the prospects of high-voltage (HV) silicon carbide (SiC) drift step recovery diode (DSRD) on pulsed power field and feasibility of outputting pulse with fast rise rate, a parallel trigger circuit is adopted and the circuit parameters affecting pulse characteristics are discussed. The simulation model of the circuit based on Sentaurus TCAD is established, in which the effects of various circuit parameters on the peak voltage and the prepulse voltage of output pulse are discussed, including the forward pumping time, the input voltage, and the inductance of reverse loop. The suitable forward pumping time and reverse loop inductance value are determined as 80 ns and 200 nH in this circuit, respectively. Experiments show that the 2.302-kV output pulse with the rise time of 1.236 ns can be obtained by HV SiC DSRD developed in our laboratory. Excluding the influence of HV probe, the actual rise time is 1.011 ns. To reduce prepulse voltage, it is effective to increase the input voltage or the inductance value of reverse loop, while the forward pumping time has little influence on it. Along with the increase of input voltage, the peak value and the rise rate of output pulse increase. Consequently, in order to improve the quality of output pulse, the input voltage should not be too low (≥200 V), while the forward pumping time and the inductance value of reverse loop should be moderate.

Comparative Studies of High-Voltage Diode-Dynistor Generators of High-Power Nanosecond Pulses

The results of comparative studies of two compact generators of nanosecond high-voltage pulses are presented. Both generators include an opening switch in the form of a block of drift step-recovery diodes (DSRDs) and a closing switch in the form of a block of shock-ionized dynistors (SIDs). The generators are designed according to two different schemes, but they have similar parameters of the output pulses on a load of <inline-formula> <tex-math notation="LaTeX">$50~\Omega $ </tex-math></inline-formula>: the amplitude of the output voltage is &#x007E; 30 kV, its rise time is &#x007E; 3 ns, and the output energy is &#x007E; 0.4 J. It is shown that it is possible to increase the output voltage and output energy of the generators.

Erratum to: A High-Voltage High-Frequency Subnanosecond Pulse Generator Based on Gallium Arsenide Drift Step-Recovery Diodes

Erratum to: A High-Voltage High-Frequency Subnanosecond Pulse Generator Based on Gallium Arsenide Drift Step-Recovery Diodes

Stacked Diodes for Pulsed Power Applications: New Process Integration Scheme

Since Boff, Moll, and Shen’s discovery of the high-speed switching effect inherent in initially forward-biased silicon diodes that are suddenly reverse-biased in 1960 [1]; DSRD’s (as termed by Grekhov and Kardo-Sysoev in 1985 [2]) performance has not increased as their deep-diffusion manufacturing process remains the same as it was over 60 years ago. Albeit new pulse generator topologies which utilize diodes like DSRDs, i.e., SOS diodes (termed by Rukin in 1992 [3]) have shown improvement at circuit level given they operate under a higher direct-current density compared to that of DSRD-based pulsers – the voltage-to-risetime, dV/dt, of these silicon-based solid-state diodes remain on the order of 1012 V/s. Furthermore, all possible ways to improve pulse performance of DSRD made by deep diffusion have been extensively investigated and exhausted. To achieve the 1013 V/s (10 kV/ns) voltage-to-risetime required by an all-solid-state pulse generation utilized to support of the missions, improving DSRD manufacturing techniques must ensue.The process flow is schematically illustrated by Fig. 1. On starting degenerate doped wafer, two epitaxial layers are grown, first n- then p-type doped thus forming p-n junction of the diode.The doping profile is controlled by changing dopant flow into epi chamber. It allows getting an optimal diode doping profile predicted by simulation. Notice, the old diffusion process allows only predetermined doping profile (complementary error function) which is not optimal.After forming the blanket p-n junction structure on entire wafers, individual diode dies are separated by wafer patterning. Though the wafers remain intact. This is opposite to the old process where the wafers were cut into individual diode dies. In our technology, V-grooves are formed by anisotropic etching process resulting in structure shown on Fig. 2. Squares surrounded by the v-grooves will become diodes, Inner slopes of v-grooves become side walls of the diodes. Notice, in old technology side walls were usually vertical, which creates a weak point for electrical breakdown: it is limited by surfacee breakdown properties, not bulk silicon properties.Next is diode side surface insulation. It is achieved by thermal oxidation. Thus, the diodes get the best surface passivation (i.e., thermal SiO2). The p-n junction is located near middle of the V-groove slope. Thus, there is no local spike of electric field where avalanche breakdown starts. Eventually, the breakdown properties of this diode are much closer to bulk silicon limit – as compared to old technology where the breakdown was surface limited.At next stage the silicon dioxide layer is removed on top surface but remains on v-groove slopes. Now we have wafers with diode arrays, terminated and passivated by side surfaces.Further, selective electroplating of copper is performed to form electrical contacts. Also, it is a step in preparation to wafer stacking. In old technology, metallization was at much earlier stage of flow and thus it interfered with side insulation. In selective electroplating, copper is deposited only on silicon surfaces, and does not deposit on SiO2 surfaces of v-groove insulation.To finish preparation for wafer bonding, tin is selectively deposited over copper. Then, wafers are aligned and stacked. The wafer stack is heated above tin melting temperature. By solid-liquid interdiffusion, Cu/Sn intermetallic compound is formed. It has much higher melting point compared to tin. Bonding process continues until entire tin layer is consumed.Now the bonded wafer stack is ready for last step in the processing – cutting into stacked DSRDs. The cutting is regular mechanical sawing. The saw lines are along the lines of v-grove bottoms.The process and resulting device design are patented [4].On next step of this project, electrical performance of final stacked DSRDs will be compared to performance of stacked DSRDs manufactured by traditional deep diffusion-based technology. Boff, A., J. Moll, and R. Shen. "A new high-speed effect in solid-state diodes." in 1960 IEEE International Solid-State Circuits Conference. Digest of Technical Papers, vol. 3, pp. 50-51. IEEE, 1960. Grekhov, I. V., V. M. Efanov, A. F. Kardo-Sysoev, and S. V. Shenderey. "Power drift step recovery diodes (DSRD)." Solid-State Electronics 28, no. 6 (1985): 597-599..Rukin, S. N. "Pulsed power technology based on semiconductor opening switches: A review." Review of Scientific Instruments 91, no. 1 (2020): 011501.Bellinger, A.Caruso, A.Usenko, US Patent Application “Stacked Diode with Side Passivation and Method of Making the Same” filed 09/10/2021. Figure 1

A High-Power Diode\u2013Dynistor Generator for Gas-Discharge Technologies

A high-voltage pulse generator is considered that contains an output circuit based on series-connected assemblies of reverse switched-on dynistors and drift step-recovery diodes. It forms voltage pulses with a rise time of 4 ns and an amplitude of 24 kV across a load of 50 Ω. The results of using the generator for creating discharges in atmospheric air are presented. The generator forms discharge-current pulses with an amplitude of 1.7 kА and a rise time of 900 ns at a frequency of 100 Hz and switches an energy of ~3 J to the charge channel. The possibility of a significant increase in the switched energy has been shown.

A High-Voltage High-Frequency Subnanosecond Pulse Generator Based on Gallium Arsenide Drift Step-Recovery Diodes

The prospect of using high-voltage GaAs drift step-recovery diodes for the formation of subnanosecond pulses is shown. The electrical circuit of a generator is described, which provides (with a total efficiency of at least 25%) the formation of pulses at a load of 50 Ω with an amplitude of up to 550 V, a voltage rise time of 0.43 ns, a full width at half maximum of 0.73 ns, and a repetition frequency of up to 200 kHz.

Driving mechanism of drift-step-recovery diodes.

Parameters governing forward and reverse pumping of a device mechanism have an important influence on the cutoff and output characteristics of a drift-step-recovery diode (DSRD). Therefore, we analyzed the driving circuit for the DSRD that was used to adjust pumping parameter values. With multiple modules in parallel, a driving method exploiting narrow-pulse pumping is proposed in developing a high-repetition-frequency DSRD pulse generator. In experiments and simulations, one key factor affecting the working stability of this pulse generator operating at repetition frequencies in the megahertz range was found that helped in further optimizing the parameter settings of our 2 kV DSRD driving circuit. From this insight, a 2 kV-5MHz all-solid-state high-repetition-frequency pulse generator based on the DSRD was developed.

4H-SiC Drift Step Recovery Diode with Super Junction for Hard Recovery.

Silicon carbide (SiC) drift step recovery diode (DSRD) is a kind of opening-type pulsed power device with wide bandgap material. The super junction (SJ) structure is introduced in the SiC DSRD for the first time in this paper, in order to increase the hardness of the recovery process, and improve the blocking capability at the same time. The device model of the SJ SiC DSRD is established and its breakdown principle is verified. The effects of various structure parameters including the concentration, the thickness, and the width of the SJ layer on the electrical characteristics of the SJ SiC DSRD are discussed. The characteristics of the SJ SiC DSRD and the conventional SiC DSRD are compared. The results show that the breakdown voltage of the SJ SiC DSRD is 28% higher than that of the conventional SiC DSRD, and the dv/dt output by the circuit based on SJ SiC DSRD is 31% higher than that of conventional SiC DSRD. It is verified that the SJ SiC DSRD can achieve higher voltage, higher cut-off current and harder recovery characteristics than the conventional SiC DSRD, so as to output a higher dv/dt voltage on the load.

Study on All-Solid High Repetition-Rate Pulse Generator Based on DSRD

The pulse generator based on drift step recovery diode (DSRD) has broad development prospects in the research of high pulse repetition frequency (PRF), high power pulse generators. In this letter, a pulse generator based on DSRD is successfully developed. The design of circuit topology and design principles are presented. The pulse generator can work stably outputting almost 30kV peak voltage at 100 kHz PRF or 140kV at 25kHz with a 50kΩ load. What's more, the influences of power supply voltage and load resistance are studied experimentally.

Development of the high repetitive frequency solid-state pulse generator based on DSRD

This paper presents a solid-state pulse generator based on drift step recovery diode (DSRD) - a new high-power, ultra-fast semiconductor opening switch, and a saturable pulse transformer. The topology structure of circuit is designed, the operating principle of the pulse generator is analyzed theoretically. And the influence of several key circuit parameters on the output waveform of the pulse generator is studied, including the coil winding turns, the magnetic core layers, the load resistance, and the trigger pulse width. The experimental results show that the pulse generator can produce a pulse at a 50 kΩ-resistive load with amplitude 38.2 kV, rise time 7.1 ns, pulse width 14.1 ns, output peak power 29.2kW, and it could work stably at the repetition frequency of 400 kHz.

Study of the features of ultrafast silicon-carbide current switch for sources of soft x-ray radiation based on capillary plasma

The results of the development and experimental investigation of high-voltage silicon-carbide high-speed current switches – drift step recovery diodes (DSRD) – and their implementation as a part of soft X-ray source based on capillary plasma are presented.